During the ISH Frankfurt show in March 1999, I was exposed to a product that made my mind race. I saw, for the first time, a variable-speed, constant-pressure, variable-flow concept circulator for use in residential hydronic applications.

The introduction of this product to the North American market has been a long time in coming. There were technical issues with voltage and hertz incompatibility with the North America electrical grid, and the typical North American hydronic heating contractor would need to educate himself about how to apply this new product.

Cutting-edge U.S. contractors wanted a circulator that could be programmed to maintain a given pressure differential, using variable-speed operation, state-of-the-art control logic and state-of-the-art, high-efficiency electrically commutated motors. We wanted this circulator to have options in programming that would allow us to vary the speed around a temperature differential, if necessary, or operate to maintain a given pressure differential regardless of how many zones were open. And these pumps were available, if you were contracting in Europe.

Fast forward to late 2006. I received an e-mail from a German pump manufacturer called Wilo (pronounced VEE-lo). Company representatives contacted me and a few other North American hydronic designers to see if we would be willing to travel to Dortmund, Germany, to tour their manufacturing facility and preview a series of products that Wilo was getting ready to release to the North American market. I quickly cleared my schedule and found myself taking the tour of a lifetime with three like-minded traveling companions, seeing the insides of hydronic heating systems about which the typical North American hydronic heating contractor can only dream.

I traveled with hydronic expert John Siegenthaler and the equally qualified and passionate Bill Shady, both fine mechanical engineers, and our host and guide, Steve Thompson, Wilo North America's vice president/education. It was a whirlwind, five-day trip jammed with techno-speak and tours of hydronics done the European way.

This new product that Wilo was getting ready to introduce to the North American market was its U.L.-approved version of the Stratos pump. This pump, which has been used in Europe for about six years, was going to be rolled out to the North American market. It can change the way the smart North American hydronic heating contractor does business.

The days of inexpensive electricity are long gone, and with it went the walls lined with a circulator for each zone. With the "build green" movement well under way, we hydronic heating contractors have to sharpen our skills and provide the biggest bang for the lowest watt. This means having to reconsider how we design hydronic heating systems. It doesn't necessarily limit us to having to use one temperature, although that is sage advice. It does, however, mean that we won't be using a jillion watts of power where a few hundred would do the trick. It also means that we won't need to incorporate pressure-activated bypasses into our basic hydronic designs. These new circulators will eliminate the need for that component alone.

I explained to my German hosts that this meant that we as hydronic educators were going to have to re-educate the North American contractor on how to properly apply these new variablespeed circulators. This is a challenge, though, that I was willing to take on and incorporate into the classes that I teach at Red Rocks Community College. My hosts, then, unveiled their teaching tool, dubbed the Brain Box, which can mimic and demonstrate changing conditions within a hydronic system.

Tune in next month as we continue our journey into the future of high-efficiency hydronic pumping. Until then, Happy Variable-Speed Hydronicing.

Mark Eatherton is a Denver-based hydronics contractor. He can be reached via e-mail at markeatherton@comcast.net or by phone at 303/778-7772.

More articles on hydronics by Mark Eatherton